There are many sources of energy that are either significantly underused or are only used in limited markets. Examples of such energy sources are wind solar energy, and water power. Some, such as wind and solar power, are intermittent. All, at present, require connection to an electrical grid to transmit the power from the generation points to the points of use.
More energy from sunlight strikes the Earth in one hour than all the energy consumed on the earth in a year. Although the solar electricity is a 7.5 billion industry which was growing at the rate of 35-40% per annum in 2001, in that year, it produced less than 0.1% of the world's electricity. The huge gap between our present use of solar energy and its underdeveloped potential defines a grand challenge in energy research. Covering 0.16% of the land of the Earth with 10% efficient solar conversion systems would provide 20 TW of power, nearly twice the world's consumption rate of fossil energy.
Many renewable resources are intermittent, i.e., they are not available all the time. Efficient storage of energy from renewable sources allows supply to more closely match demand. For example, a storage system that can store energy captured around the clock and dispatch that energy into the higher priced mid-day market would allow solar energy to be used day or night.
The U.S. Department of Energy has said that an improved method of storage of electrical energy is one of the main challenges preventing the substantial installation of renewable energies such as wind and solar power. Storage is vital for times when the wind does not blow or the sun does not shine. During those times, stored electrical energy can get to the electrical grid as needed.
An idea of the potential of one form of renewable energy, solar power, is provided by Professor David Falman of Israel's Ben Gurion University, who says that a series of solar energy power stations in the Negev could supply all of Israel's power needs and that all of the world's electrical needs could be supplied with the solar power stations covering slightly less than 10 percent of the Sahara.
However, use of solar power, wind power, water power, or any other source of power where it is desired to produce the power a location remote from the location of use of the power, requires a means for transporting the power from one location to another. Building electrical grids over long distances can be extremely costly. Furthermore, in many cases, such as automobiles, connection to a grid during use is not acceptable.
Therefore, there is a long-felt need for a means of production of energy that does not depend on connection to an electrical grid or other fixed installation to transport the energy to the point of use thereof.